JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式。它基于ECMAScript的一个子集。 JSON采用完全独立于语言的文本格式,但是也使用了类似于C语言家族的习惯(包括C、C++、C#、Java、JavaScript、Perl、Python等)。这些特性使JSON成为理想的数据交换语言。 易于人阅读和编写,同时也易于机器解析和生成(一般用于提升网络传输速率)。
json简单说就是javascript中的对象和数组,所以这两种结构就是对象和数组两种结构,通过这两种结构可以表示各种复杂的结构。
1、对象:对象在js中表示为“{}”括起来的内容,数据结构为 {key:value,key:value,...}的键值对的结构,在面向对象的语言中,key为对象的属性,value为对应的属性值,所以很容易理解,取值方法为 对象.key 获取属性值,这个属性值的类型可以是 数字、字符串、数组、对象几种。
2、数组:数组在js中是中括号“[]”括起来的内容,数据结构为 ["java","javascript","vb",...],取值方式和所有语言中一样,使用索引获取,字段值的类型可以是 数字、字符串、数组、对象几种。
经过对象、数组2种结构就可以组合成复杂的数据结构了。
使用JSON前需要先的导入json.jar包
传输单个对象:
新建一个 servlet
package com.itnba.maya.a;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONObject;
/** * Servlet implementation class C */@WebServlet("/C")public class C extends HttpServlet {
private static final long serialVersionUID = 1L;
/** * @see HttpServlet#HttpServlet() */ public C() {
super();
// TODO Auto-generated constructor stub }
/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
//模拟从数据库中查处 Dog a=new Dog();
a.setName("小黄");
a.setAge(5);
a.setZl("哈士奇");
JSONObject obj=new JSONObject();
obj.put("name", a.getName());
obj.put("age", a.getAge());
obj.put("zl", a.getZl());
JSONObject bb=new JSONObject();
bb.put("obj", obj);
response.getWriter().append(bb.toString());
}
/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub doGet(request, response);
}
}
效果如下:
jsp页面
<%@ page language="java" contentType="text/html;
charset=utf-8" pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html;
charset=utf-8"><title>Insert title here</title><script type="text/javascript" src="js/jquery-1.11.1.min.js"></script><script type="text/javascript">$(document).ready(function(){
$("#k").click(function(){
$.ajax({
url:"C", data:{
}
, type:"POST", dataType:"JSON", success:function(httpdata){
$("#x").append("<li>"+httpdata.obj.name+"</li>");
$("#x").append("<li>"+httpdata.obj.age+"</li>");
$("#x").append("<li>"+httpdata.obj.zl+"</li>") }
}
) }
);
}
);
</script></head><body><span id="k">查看</span><h1><ul id="x"></ul></h1></body></html>
效果如下:
传输集合或数组:
servlet:
package com.itnba.maya.a;
import java.io.IOException;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONArray;
import org.json.JSONObject;
/** * Servlet implementation class D */@WebServlet("/D")public class D extends HttpServlet {
private static final long serialVersionUID = 1L;
/** * @see HttpServlet#HttpServlet() */ public D() {
super();
// TODO Auto-generated constructor stub }
/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
//模拟从数据库中查出 Dog a1=new Dog();
a1.setName("小黄");
a1.setAge(5);
a1.setZl("哈士奇");
Dog a2=new Dog();
a2.setName("中黄");
a2.setAge(6);
a2.setZl("泰迪");
Dog a3=new Dog();
a3.setName("大黄");
a3.setAge(7);
a3.setZl("京巴");
ArrayList<Dog> list=new ArrayList<Dog>();
list.add(a1);
list.add(a2);
list.add(a3);
JSONArray arr= new JSONArray();
//遍历集合 for(Dog d:list){
JSONObject obj=new JSONObject();
obj.put("name", d.getName());
obj.put("age", d.getAge());
obj.put("zl", d.getZl());
arr.put(obj);
}
response.getWriter().append(arr.toString());
}
/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub doGet(request, response);
}
}
效果如下:
jsp页面:
<%@ page language="java" contentType="text/html;
charset=utf-8" pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html;
charset=utf-8"><title>Insert title here</title><script type="text/javascript" src="js/jquery-1.11.1.min.js"></script><script type="text/javascript">$(document).ready(function(){
$("#k").click(function(){
$.ajax({
url:"D", data:{
}
, type:"POST", dataType:"JSON", success:function(httpdata){
for(var i=0;
i<httpdata.length;
i++){
var n=httpdata[i].name var a=httpdata[i].age var z=httpdata[i].zl var tr="<tr>" tr+="<td>"+n+"</td>" tr+="<td>"+a+"</td>" tr+="<td>"+z+"</td>" tr+="</tr>" $("#x").append(tr) }
}
}
) }
);
}
);
</script></head><body><span id="k">查看</span><h1><table width="100%" id="x" border="1px"></table></h1></body></html>
效果如下:
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